To promote public safety, facilitate the movement of traffic, preserve the public’s financial investment in highways, promote the national defense, and accomplish the purposes of this chapter, the commission may:
(1) lay out, construct, maintain, and operate a modern state highway system, with emphasis on the construction of controlled access highways;
(2) plan for future highways; and
(3) convert where necessary an existing street, road, or highway into a controlled access highway in accordance with modern standards of speed and safety.